Well, it's interesting math for sure. But all of this is based on the assumption that you would own a 48 mpg Prius over a 32 mpg Ford Escape mainly to save money on gas, when driving around 38 000 miles per year, at 75 miles per hour? Or vice versa, if the cost difference is small, you might go for the Escape.

Hmmmm. Being green can indeed be a challenge at times.